Energy filter for processing a power semiconductor device

ABSTRACT

A method of producing an implantation ion energy filter, suitable for processing a power semiconductor device. In one example, the method includes creating a preform having a first structure; providing an energy filter body material; and structuring the energy filter body material by using the preform, thereby establishing an energy filter body having a second structure.

CROSS-REFERENCE TO RELATED APPLICATION

This Utility Patent Application claims priority to German PatentApplication No. 10 2016 110 429.9, filed Jun. 6, 2016, which isincorporated herein by reference.

TECHNICAL FIELD

This specification refers to embodiments of an implantation ion energyfilter, to embodiments of a method of producing an implantation ionenergy filter and to embodiments of processing a power semiconductordevice. In particular, this specification is directed to embodiments ofan implantation ion energy filter to be used during an ion implantationwithin the scope of processing a power semiconductor device, toembodiments of a method of producing such implantation ion energy filterand to embodiments of a method of processing a power semiconductordevice employing such implantation ion energy filter.

BACKGROUND

Many functions of modern devices in automotive, consumer and industrialapplications, such as converting electrical energy and driving anelectric motor or an electric machine, rely on power semiconductordevices. For example, Insulated Gate Bipolar Transistors (IGBTs), MetalOxide Semiconductor Field Effect Transistors (MOSFETs) and diodes, toname a few, have been used for various applications including, but notlimited to switches in power supplies and power converters.

Such a power semiconductor device is usually based on a semiconductorbody that may be configured to conduct load current between at least twoload terminals of the device. In order to ensure a load currentcapability, a blocking capability and/or a switching capability of thedevice, the semiconductor body may comprise one or more semiconductorregions exhibiting a specific dopant configuration. For example, suchsemiconductor regions may include a source region, a channel region(also referred to as body region), a field stop region, an emitterregion, a superjunction structure (also referred to as compensationstructure) and/or guard rings, to name a few examples.

Each of said semiconductor regions may include dopants of the firstconductivity type, e.g., n-type dopants, and/or dopants of secondconductivity type, e.g., p-type dopants, and each of the saidsemiconductor regions may exhibit a specific dopant concentrationprofile.

In order to create doped semiconductor regions in the semiconductorbody, certain semiconductor device processing steps can be carried out,e.g., a diffusion processing step, an epitaxy processing step and/or anion implantation processing step.

Regarding the ion implantation, an implantation apparatus may provideimplantation ions and accelerate these along an extension directiontowards a semiconductor body. In order to create a specific dopantconcentration in the extension direction within the semiconductor body,in addition to a mask, a so-called implantation ion energy filter may bepositioned between said implantation apparatus and the semiconductorbody such that the implantation ions traverse the filter prior toentering the semiconductor body.

SUMMARY

According to an embodiment, a method of producing an implantation ionenergy filter comprises: creating a preform having a first structure;providing an energy filter body material; and structuring the energyfilter body material by using the preform, thereby establishing anenergy filter body having a second structure.

According to a further embodiment, a method of processing a powersemiconductor device comprises: providing a semiconductor body;producing, in the semiconductor body, at least one first semiconductorregion doped with dopants of a first conductivity type by applying afirst implantation of first implantation ions, said applying of saidfirst implantation is carried out such that the first implantation ionstraverse an energy filter prior to entering the semiconductor body,wherein the energy filter has been produced by creating a preform havinga first structure; providing an energy filter body material; andstructuring the energy filter body material by using the preform,thereby establishing an energy filter body having a second structure.

According to a yet further embodiment, an implantation ion energy filtercomprises an energy filter body having a structure, wherein the energyfilter body is configured to receive implantation ions and to outputreceived implantation ions such that the output implantation ionsexhibit a reduced energy as compared to their energy when entering theenergy filter body; and wherein the energy filter body is made of anenergy filter body material comprising a glass.

Those skilled in the art will recognize additional features andadvantages upon reading the following detailed description, and uponviewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The parts in the figures are not necessarily to scale, instead emphasisbeing placed upon illustrating principles of the invention. Moreover, inthe figures, like reference numerals designate corresponding parts. Inthe drawings:

FIG. 1 schematically and exemplarily illustrates a section of a verticalcross-section of a power semiconductor device being subjected to an ionimplantation in accordance with one or more embodiments;

FIG. 2 schematically and exemplarily illustrates a section of a verticalcross-section of a power semiconductor device being subjected to an ionimplantation along with a schematic illustration of an exemplary dopantconcentration profile in accordance with one or more embodiments;

FIGS. 3A-F each schematically and exemplarily illustrate a section of avertical cross-section of an implantation ion energy filter inaccordance with one or more embodiments;

FIGS. 4A-B each schematically and exemplarily illustrate a section of avertical cross-section of a preform in accordance with one or moreembodiments;

FIGS. 5-9 each schematically and exemplarily illustrate, based onillustrations of sections of vertical cross-section of an exemplaryenergy filter body and an exemplary preform, steps of a method ofproducing an implantation ion energy filter in accordance with one ormore embodiments;

FIG. 10 schematically and exemplarily illustrates a diagram of a methodof producing an implantation ion energy filter in accordance with one ormore embodiments; and

FIG. 11 schematically and exemplarily illustrates a diagram of a methodof processing a power semiconductor device in accordance with one ormore embodiments; and

FIG. 12 schematically and exemplarily illustrates a section of avertical cross-section of an implantation ion energy filter inaccordance with one or more embodiments.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof and in which are shown byway of illustration specific embodiments in which the invention may bepracticed.

In this regard, directional terminology, such as “top”, “bottom”,“below”, “front”, “behind”, “back”, “leading”, “trailing”, “below”,“above” etc., may be used with reference to the orientation of thefigures being described. Because parts of embodiments can be positionedin a number of different orientations, the directional terminology isused for purposes of illustration and is in no way limiting. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope of thepresent invention. The following detailed description, therefore, is notto be taken in a limiting sense, and the scope of the present inventionis defined by the appended claims.

Reference will now be made in detail to various embodiments, one or moreexamples of which are illustrated in the figures. Each example isprovided by way of explanation, and is not meant as a limitation of theinvention. For example, features illustrated or described as part of oneembodiment can be used on or in conjunction with other embodiments toyield yet a further embodiment. It is intended that the presentinvention includes such modifications and variations. The examples aredescribed using specific language which should not be construed aslimiting the scope of the appended claims. The drawings are not scaledand are for illustrative purposes only. For clarity, the same elementsor manufacturing steps have been designated by the same references inthe different drawings if not stated otherwise.

The term “horizontal” as used in this specification intends to describean orientation substantially parallel to a horizontal surface of asemiconductor substrate or of a semiconductor structure. This can be forinstance the surface of a semiconductor wafer or a die. For example,both the first lateral direction X and the second lateral direction Ymentioned below can be horizontal directions, wherein the first lateraldirection X and the second lateral direction Y may be perpendicular toeach other.

The term “vertical” as used in this specification intends to describe anorientation which is substantially arranged perpendicular to thehorizontal surface, i.e., parallel to the normal direction of thesurface of the semiconductor wafer. For example, the extension directionZ mentioned below may be an extension direction that is perpendicular toboth the first lateral direction X and the second lateral direction Y.

In this specification, n-doped is referred to as “first conductivitytype” while p-doped is referred to as “second conductivity type”.Alternatively, opposite doping relations can be employed so that thefirst conductivity type can be p-doped and the second conductivity typecan be n-doped.

In the context of the present specification, the terms “in ohmiccontact”, “in electric contact”, “in ohmic connection”, and“electrically connected” intend to describe that there is a low ohmicelectric connection or low ohmic current path between two regions,sections, zones, portions or parts of a semiconductor device or betweendifferent terminals of one or more devices or between a terminal or ametallization or an electrode and a portion or part of a semiconductordevice. Further, in the context of the present specification, the term“in contact” intends to describe that there is a direct physicalconnection between two elements of the respective semiconductor device;e.g., a transition between two elements being in contact with each othermay not include a further intermediate element or the like.

In addition, in the context of the present specification, the term“electric insulation” is used, if not stated otherwise, in the contextof its general valid understanding and thus intends to describe that twoor more components are positioned separately from each other and thatthere is no ohmic connection connecting those components. However,components being electrically insulated from each other may neverthelessbe coupled to each other, for example mechanically coupled and/orcapacitively coupled and/or inductively coupled. To give an example, twoelectrodes of a capacitor may be electrically insulated from each otherand, at the same time, mechanically and capacitively coupled to eachother, e.g., by means of an insulation, e.g., a dielectric.

Specific embodiments described in this specification pertain to, withoutbeing limited thereto, a power semiconductor device, such as a powersemiconductor transistor, that may be used within a power converter or apower supply. Thus, in an embodiment, the semiconductor device isconfigured to carry a load current that is to be fed to a load and/or,respectively, that is provided by a power source. For example, thesemiconductor device may comprise one or more active power semiconductorcells, such as a monolithically integrated diode cell, and/or amonolithically integrated transistor cell, and/or a monolithicallyintegrated IGBT cell, and/or a monolithically integrated RC-IGBT cell,and/or a monolithically integrated MOS Gated Diode (MGD) cell, and/or amonolithically integrated MOSFET cell and/or derivatives thereof. Suchdiode cell and/or such transistor cells may be integrated in a powersemiconductor module. A plurality of such cells may constitute a cellfield that is arranged with an active region of the power semiconductordevice.

The term “power semiconductor device” as used in this specificationintends to describe a semiconductor device on a single chip with highvoltage blocking and/or high current-carrying capabilities. In otherwords, such power semiconductor device is intended for high current,typically in the Ampere range, e.g., up to several ten or hundredAmpere, and/or high voltages, typically above 15 V, more typically 100 Vand above, e.g., up to at least 400 V, e.g., greater than 1 kV, or evengreater than 3 kV. For example, the processed power semiconductor devicedescribed below may be a semiconductor device exhibiting a stripe cellconfiguration or a needle cell configuration and can be configured to beemployed as a power component in a low-, medium- and/or high voltageapplication.

FIG. 10 schematically and exemplarily illustrates a diagram of anembodiment of a method 5 of producing an implantation ion energy filter.In step 52, a preform is created that has a first structure. In anotherstep 54, which can be carried out before, simultaneously to, or afterstep 52, an energy filter body material is provided. In a subsequentstep 56, the energy filter body material is structured by using thepreform. Thereby, an energy filter body can be established that has asecond structure. For example, the structured energy filter body 32forms the implantation ion energy filter 3 (also referred to as energyfilter in the following).

FIG. 11 schematically and exemplarily illustrates a diagram of anembodiment of a method of processing a power semiconductor device. Instep 22, a semiconductor body 10 is provided. The provided semiconductorbody 10 may comprise or, respectively, be made of a semiconductor bodymaterial having a dopant diffusion coefficient smaller than the dopantdiffusion coefficient of silicon. For example, the semiconductor bodymaterial may have a dopant diffusion coefficient at least two orders ofmagnitude lower than the corresponding dopant diffusion coefficient ofsilicon. Said diffusion coefficient may comprise at least one of anacceptor diffusion coefficient and a donor diffusion coefficient. Thesemiconductor body 10 may be made of a material comprising at least oneof silicon carbide, gallium nitride, aluminum nitride. In a subsequentstep 24, at least one first semiconductor region is produced in thesemiconductor body, the at least one first semiconductor region beingdoped with dopants of a first conductivity type. Said producing can becarried out by applying a first implantation of first implantation ions,wherein said applying of said first implantation can be carried out suchthat the first implantation ions traverse an energy filter prior toentering the semiconductor body. The energy filter may have beenproduced by creating a preform having a first structure; by providing anenergy filter body material; and by structuring the energy filter bodymaterial by using the preform, thereby establishing an energy filterbody having a second structure.

FIG. 12 schematically and exemplarily illustrates a section of avertical cross-section of an embodiment of an implantation ion energyfilter 3. The implantation ion energy filter 3 may be configured to beused during an ion implantation within the scope of processing a powersemiconductor device. For example, implantation ions 80 are provided byan implantation apparatus 8, and the implantation ions 80 are beingaccelerated along an extension direction Z towards a semiconductor body10. The implantation ion energy filter 3 may be positioned between saidimplantation apparatus 8 and the semiconductor body 10 such that theimplantation ions 80 traverse the filter 3 prior to entering thesemiconductor body 10. For example, the implantation ion energy filter 3comprises an energy filter body 32 having a structure 322. Further, theenergy filter body 32 can be configured to receive implantation ions 80and to output received implantation ions such that the outputimplantation ions 80 exhibit a reduced energy as compared to theirenergy when entering the energy filter. The energy filter body 32 can bemade of an energy filter body material comprising a glass. For example,the glass comprises at least one of

-   -   borosilicate glass,    -   a soda-lime glass,    -   a float glass,    -   a quartz glass,    -   a porcelain,    -   a polymer thermoplastic,    -   a polymer glass,    -   an acrylic glass,    -   polycarbonate,    -   polyethylene terephthalate,    -   a silica doped with at least one dopant, the at least one dopant        being selected from a group containing boron (B), sodium (Na),        calcium (Ca), potassium (K) and aluminum (Al), zinc (Zn), copper        (Cu), magnesium (Mg), germanium (Ge),    -   a polymer,    -   polynorbornene,    -   polystyrene,    -   polycarbonate,    -   polyimide, and    -   benzocy clobutene.

For example, the glass does not comprise silicon dioxide.

In an embodiment, the energy filter body material 32 exhibits aplasticity within a first temperature range and is stable in form withina second temperature range, the second temperature range being lowerthan the first temperature. For example, the energy filter body material32 is an amorphous solid, e.g., an amorphous solid that exhibits aplasticity within the first temperature range and is stable in formwithin the second temperature range, the second temperature range beinglower than the first temperature. For example, the first temperaturerange is smaller than a melting point of the preform 31. Further, thefirst temperature range may be greater than a comparatively highthreshold value so as to allow for high ions currents during theimplantation without changing the energy filter's form.

For example, regarding the method 5, structuring (cf. step 56) theenergy filter body material 32 by using the preform 31 may includewarming up the energy filter body material 32 to a temperature withinsaid first temperature range. In an embodiment, as indicated above, theenergy filter body material 32 may comprise a glass. Then, structuring(cf. step 56) the energy filter body material 32 may include warming upthe energy filter body material 32 to a temperature of at least 90%, ofat least 95%, or to a temperature of at least 98% of a glass-transitiontemperature of the energy filter body material 32. For example, theglass-transition temperature of the energy filter body material 32 maybe within the first temperature range.

Further, regarding the method 2, during producing (cf. step 24) the atleast one first semiconductor region 11 in the semiconductor body 10 byapplying the first implantation such that first implantation ionstraverse the energy filter 3, e.g., its energy filter body 32, theenergy filter body 32 can be kept at a temperature within the secondtemperature range.

For example, for a chosen energy filter body material, the firsttemperature range may include values in between 1000° C. to 1400° C.,and the second temperature range may include values smaller than 900° C.In an embodiment, the lowest temperature value of the first temperaturerange is greater by at least 100° C. then the highest temperature valueof the second temperature range.

Exemplary aspects of the aforementioned embodiments of the method 5 ofproducing an implantation ion energy filter 3, of the method 2 ofprocessing a power semiconductor device, and of the implantation ionenergy filter 3 shall now be explained in greater detail with respect toFIGS. 1 to 9. Thus, it should be understood, but will now be statedabout the embodiments schematically and exemplarily illustrated in FIGS.1 to 9 may also apply to the embodiments schematically and exemplarilyillustrated in FIGS. 10 to 12, if not explicitly stated otherwise.

FIG. 1 schematically and exemplarily illustrates a section of a verticalcross-section of a power semiconductor device 1 being subjected to anion implantation 28. For example, the power semiconductor device 1comprises a semiconductor body 10 having a substrate region 15, whichcan be, e.g., highly doped n-region. The semiconductor body 10 maycomprise or, respectively, be made of a semiconductor body materialhaving a dopant diffusion coefficient smaller than the dopant diffusioncoefficient of silicon. For example, the semiconductor body material mayhave a dopant diffusion coefficient at least two orders of magnitudelower than the corresponding dopant diffusion coefficient of silicon.Said diffusion coefficient may comprise at least one of an acceptordiffusion coefficient and a donor diffusion coefficient. Thesemiconductor body 10 may be made of a material comprising at least oneof silicon carbide, gallium nitride, aluminum nitride. During theimplantation 28, a surface 10-1 of the semiconductor body 10 may becovered with a mask 4 having one or more openings 42. In anotherembodiment, the entire surface 10-1 may become subjected to theimplantation 28 and, e.g., no mask is employed. If a mask 4 is employed,said openings 42 may allow implantation ions to penetrate the surface10-1 of the semiconductor body 10 such that one or more firstsemiconductor regions 11 can be created within the semiconductor body10. For example, by means of the implantation 28, first semiconductorregions 11 can be created that exhibit dopants of the first conductivitytype and that are arranged adjacent to a second semiconductor region 12of the semiconductor body 10. For example, the second semiconductorregion 12 adjacent to the first semiconductor regions 11 can be dopedwith dopants of a second conductivity type complementary to the firstconductivity type. The second semiconductor region 12 may have beenproduced by applying at least one of a second implantation 28 of secondimplantation ions, an epitaxy processing step and a diffusion processingstep.

For example, the first semiconductor regions 11 and the secondsemiconductor region 12 may form a drift volume exhibiting asuperjunction structure. Prior to entering the semiconductor body 10,the implantation ions may traverse an implantation ion energy filter 3,in the following also referred to as energy filter. For example, theenergy filter 3 may have been produced in accordance with the method 5schematically and exemplarily illustrated in FIG. 10. Further, theenergy filter 3 may be configured in the same manner as the energyfilter 3 schematically and exemplarily illustrated in FIG. 12.Accordingly, the energy filter 3 may comprise an energy filter body 32that exhibits a structure 322.

As schematically and exemplarily illustrated in FIG. 2, the energyfilter 3 may be configured to receive implantation ions 281, 282 and tooutput received implantation ions such that the output implantation ionsexhibit a reduced energy E1′, E2′ as compared to their energy E1, E2when entering the energy filter 3. The respective amount of energyreduction may depend on the point and/or angle of entry into the energyfilter 3. For example, a first implantation ion 281 follows a first path71 and enters the energy filter 3 at a first point 711, exhibiting afirst energy E1. Due to the structure 322 of the energy filter 3 and dueto the first path 71 being substantially perpendicular to an inputsurface of the energy filter 3, the first implantation ion 281 traversesa comparatively thin section of the energy filter 3. Nevertheless, theenergy E1' of the output first implantation ion 281 may be reduced ascompared to the energy E1. A second implantation ion 282 may follow asecond path 72 and may enter the energy filter 3 at a second point 712,exhibiting a second energy E2. The second energy E2 may be substantiallyidentical to the first energy E1. Due to the structure 322 of the energyfilter 3 and due to the second path 72 being substantially perpendicularto the input surface of the energy filter 3, the second implantation ion282 traverses a comparatively thick section of the energy filter 3.Thus, the energy E2′ of the output second implantation ion 282 may besignificantly reduced as compared to the energy E2. Accordingly, thefirst implantation ion 281 may traverse the semiconductor body 10 alongthe extension directions Z down to a level z1, and the secondimplantation ion 282 may traverse the semiconductor body 10 along theextension directions Z down to a level z2, wherein, due to the differentamounts of energy reductions, z1 may be significantly greater than z2.For example, the difference between the levels z1 and z2 may amount toat least 1 □m, to at least 3 μm, or even to at least 5 μm. Accordingly,due to the structure 322 of the energy filter 3, a first semiconductorregion 11 may be created that exhibits a specific dopant concentrationprofile along with the extension direction Z. An exemplary dopantconcentration profile is schematically illustrated in the right part ofFIG. 2, according to which the dopant concentration profile can be aso-called box profile, i.e., the dopant concentration the firstsemiconductor region 11 may be substantially constant along theextension direction Z and amount to a value CC1. However, it shall beunderstood that, depending on the configuration of the structure 322 ofthe energy filter 32, other dopant concentration profiles may becreated, e.g., a concentration profile exhibiting one or more maxima orminima, a Gaussian dopant concentration profile, a dopant concentrationthat increases along the extension direction Z, a dopant concentrationthat decreases along the extension direction Z, a turtle shell likedopant concentration profile, to name a few examples. From thisexplanation, it becomes apparent that the energy filter 3 can also bereferred to as energy diffusor. For example, the energy filter 3 can beconfigured to convert a substantially “monochrome” ion beam into an ionbeam having a substantially continuous energy spectrum.

In accordance with an embodiment, the structure 322 of the energy filter3 extends for at least 1 cm². For example, additionally oralternatively, the structure 322 of the energy filter 3 may extend forat least the width of an ion beam of the ion implantation. Further, inan embodiment, the relevant structure sizes of the structure 322 of theenergy filter 3 may be dimensioned such that a specific dopantconcentration profile may be achieved within the semiconductor body 10.For example, the relevant structure sizes may be within the range of or,respectively, smaller than the width of the openings 42 of the mask 4.The relevant structure sizes may also be greater than the width of theopenings 42, e.g., if the energy filter 3 is spaced apart from thesurface 10-1 of the semiconductor body 10, e.g., by at least 0.5 mm.

Now referring to FIGS. 3A-F, some exemplary structures 322 of the energyfilter body 32 of embodiments of the energy filter 3 shall be explained.In accordance with the embodiment schematically illustrated in FIG. 3A,the structure 322 of the energy filter body 32 may be formed by one ormore triangular-like or pyramid-like shaped recesses. In accordance withthe embodiment schematically illustrated in FIG. 3B, the structure 322of the energy filter body 32 may be formed by one or morerectangular-like or square-like shaped recesses. In accordance with theembodiment schematically illustrated in FIG. 3C, the structure 322 ofthe energy filter body 32 may be formed by one or more trapezoid-likerecesses. In accordance with the embodiment schematically illustrated inFIG. 3D, the structure 322 of the energy filter body 32 may be formed byone or more part-circle-like or a part-ellipse-like shaped recesses. Inaccordance with the embodiment schematically illustrated in FIG. 3E, thestructure 322 of the energy filter body 32 may be formed by one or morerecesses exhibiting a stepped or graded profile. In accordance with theembodiment schematically illustrated in FIG. 3F, the structure 322 ofthe energy filter body 32 may be formed by one or more recesses having aconcave profile. Each of these aforementioned different recesses mayalso be combined with each other in single energy filter body 32 to formfurther structures 322. For example, said recesses that form thestructure 322 may be arranged on an output side (also referred to asfirst side herein) of the energy filter body 32 where the implantationions leave the energy filter body 32. Further, an input side of theenergy filter body 32 (also referred to as second side herein) where theimplantation ions may enter the energy filter body 32 can exhibitsubstantially planar surface, e.g., an unstructured surface. Inaccordance with other embodiments, also the input side of the energyfilter body 32 may be structured, e.g., for establishing a framestructure configured to ensure a stable mechanical installation of theenergy filter 3 or for establishing a structure similar or identical tothe structure 322, e.g., similar to the structure of the output side, aswill be explained in more detail below. It shall be emphasized that whathas been stated about the embodiment of the energy filter 3schematically illustrated in FIG. 12 may equally apply to theembodiments schematically illustrated in FIGS. 3A-F.

As has been explained above, producing the energy filter 3 may involvecreating a preform that has a first structure. Exemplary embodiments ofsuch preform are schematically illustrated in FIGS. 4A-B. Accordingly,the preform 31 may comprise a preform body having the first structure311. As illustrated in FIG. 4A, the first structure 311 may be formed byone or more triangular-like or pyramid-like shaped elevations. Forexample, the first structure 311 of the embodiment of the preform 31according to FIG. 4A has been produced by carrying out a wet etchprocessing step, e.g., on a semiconductor based preform 31.Alternatively or additionally, the first structure 311 may also beformed by one or more rectangular-like or square-like shaped elevations,as illustrated in FIG. 4B. For example, the first structure 311 of theembodiment of the preform 31 according to FIG. 4B has been produced bycarrying out a dry etch processing step, e.g., on a semiconductor basedpreform 31. Irrespectively of the material of the preform 31, producingthe preform 31, e.g., establishing the first structure 311, mayadditionally or alternatively include carrying out at least one of ionbeam milling, ion beam writing, wet etching, laser ablation, milling andmechanical sawing. As at least in some embodiments, the preform 31 maybe used for producing the energy filter 3, from the foregoingdescription of FIGS. 3A-F, it becomes apparent that the first structure311 of the preform 31 may also be formed by one or more elevationshaving a shape different from the elevations exemplarily illustrated inFIG. 4A and FIG. 4B. For example, the first structure 311 of the preform31 is formed by one or more elevations with a respect elevation heightDH within the range of 0.1 μm to 20 μm, or within a range of 5 μm to 10μm. Accordingly, in an example, the second structure 322 of the energyfilter 3 may be formed by one or more recesses with a respect recessdepth DD within the range of 0.1 μm to 20 μm, or within a range of 5 μmto 10 μm. Also, the widths of the elevations forming the first structure311, or respectively, the widths of the recesses forming the secondstructure 322, can be within the range of 0.1 μm to 20 μm, or within arange of 5 μm to 10 μm.

In accordance with an embodiment, the preform 31 can be made of amaterial comprising at least one of a semiconductor material, e.g.,silicon and/or silicon carbide, a ceramic, e.g., Al₂O₃ and/or Al₂TiO₅,and a high-grade steel. The material of the preform 31 may also includeone or more of silicon germanium (SiGe), binary, ternary or quaternaryIII-V semiconductor materials such as gallium nitride (GaN), galliumarsenide (GaAs), gallium phosphide (GaP), indium phosphide (InP), indiumgallium phosphide (InGaPa), aluminum gallium nitride (AlGaN), aluminumindium nitride (AlInN), indium gallium nitride (InGaN), aluminum galliumindium nitride (AlGaInN) or indium gallium arsenide phosphide (InGaAsP),and binary or ternary II-VI semiconductor materials such as cadmiumtelluride (CdTe) and mercury cadmium telluride (HgCdTe). Further, thepreform 31 may include an anti-stick coating (not illustrated) which mayseparating the preform 31 from the energy filter body 32 after thestructuring step.

For example, creating the preform 31 (cf. step 52) may compriseprocessing a base layer 310 by carrying out at least one of an

-   -   etch processing step, e.g., a wet etch processing step, e.g.,        based on an alkaline solution, and/or dry etch processing step,        e.g. including RIE and/or ion beam etching, and    -   a mechanical processing step, e.g., a milling step.

The processed base layer 310 may form the preform 31. For example, theprocessed base layer 310 is a semiconductor layer 310, e.g., based onsilicon.

As has been generally explained with respect to the embodiment of themethod 5 schematically illustrated in FIG. 10, the method 5 of producingthe energy filter 3 may include providing (cf. step 54) an energy filterbody material 32 and structuring (cf. step 56) the energy filter bodymaterial 32 by using the preform 31 so as to establish the energy filterbody 32 having the said structure 322, the latter also being referred toas second structure 322 within this specification.

In an embodiment, structuring the energy filter body material 32 mayinclude carrying out an imprint step using the preform 31 as a stamp.For example, to this end, the energy filter body material 32 may besoftened, e.g., by heating up the energy filter body material 32 suchthat it is deformable and subsequently, i.e., after the imprint step,cooling down the energy filter body material 32. For example, theimprint step may include an embossing step, e.g., a hot embossing step.Further optional aspects of the embodiment of the method where thestructuring includes carrying out the imprint step will be explained inmore detail below.

In accordance with another embodiment, structuring the energy filterbody material 32 may include carrying out at least one of a castingprocessing step and a molding processing step. Thus, for example, theenergy filter body material 32 may be heated up such that it becomesliquid and it may then be poured into the preform 31. For example, theenergy filter body material 32 may become solid within the preform 31and may subsequently be removed from the preform 31.

For example, structuring the energy filter body material 32 forestablishing the structure 322 does not include an etch processing step.

For example, the structure 322 of the energy filter body 32 may becomplementary to the structure 311 of the preform 31. For example, saidelevations forming the structure 311 of the preform 31 may define theshape of said recesses forming the structure 322 of the energy filterbody 32. Accordingly, in an embodiment, the preform 31 may be consideredas a negative form 31.

In accordance with an embodiment, a plurality of energy filter bodies32, each of which having the second structure 322, are established byusing the same preform 31. Accordingly, the preform 31 may be configuredto be used to produce a plurality of implantation ion energy filters 3,e.g., more than ten energy filters 3, more than 50 energy filters 3, oreven more than 100 energy filters 3. As in this embodiment, the samepreform 31 is used to produce a plurality of implantation ion energyfilters 3, the produced energy filters 3 do substantially not deviatefrom each other in structure 322; e.g., the structures 322 of each ofthe plurality of energy filters 3 that have been produced using the samepreform 31 may be substantially identical to each other, since each ofthe plurality of structures 322 may have been established by means ofthe first structure of the preform 31. Accordingly, a highreproducibility of a power semiconductor device, e.g., the powersemiconductor device 1 schematically illustrated in FIG. 1, e.g., theconfiguration formed by the first semiconductor regions 11 and thesecond semiconductor region 12, may be ensured. This embodiment includesthe recognition that energy filters used during ion implantation, e.g.,high energy ion implantations with energies greater than 2 MeV, withinthe scope of processing power semiconductor devices may need to bereplaced after a certain operating duration. For example, the energyfilter employed therein may become worn-out after some time.

With regards to FIGS. 5 to 9, some exemplary embodiments of the method 5of producing the energy filter 3 shall now be explained. These exemplaryembodiments of the method 5 may include common processing steps and itshall be understood that what is stated about a certain processing stepwith respect to a specific one of FIGS. 5 to 9 may equally apply to anembodiment in accordance with another one of FIGS. 5 to 9, if notexplicitly stated otherwise.

In accordance with the embodiment schematically illustrated in FIG. 5,the energy filter body material 32 is provided in step 54. As indicatedabove, the energy filter body material 32 may be provided as a solidglass, for example. In a step 561, the preform 31 having the firststructure 311 may be aligned with the provided energy filter body 32.Then, in a step 562, a force may be applied to the preform 31 such thatthe first structure 311 penetrates into the energy filter body 32,wherein the energy filter body 32 may have been softened, e.g., byheating up, before applying the force to the preform 31. Thereby, thesecond structure 322 may be established at the energy filter body 32.This structuring can be done with an imprint step, e.g., a micro-imprintstep and/or a nano-imprint step, e.g., a hot embossing step. After acertain amount of time, the preform 31 may be separated from the energyfilter body 32. Further, method 5 may include a removing step 57,wherein a section of a side of the energy filter body 32 has not beenstructured is removed, e.g., by grinding and/or etching, so as todecrease the total thickness of the energy filter body 32. Asschematically illustrated in each of FIGS. 5 to 9, the first structure311 of the preform 31 may exhibit an interruption 308 which may cause acorresponding interruption 328 in the second structure 322 of the energyfilter body 32. In an embodiment, method 5 may further include the step58 of dividing the energy filter body 32 into at least two separatebodies, wherein said dividing may be carried out at said interruption328. The dividing may include applying at least one of alaser-separation processing step and a mechanical sawing processingstep, i.e., the energy filter body 32 may be separated by means of alaser beam.

In accordance with the embodiment schematically illustrated in FIG. 6,in step 54, the energy filter body material 32 is provided as a part ofa carrier-glass-compound wafer arrangement 32, 33. For example, theenergy filter body material 32 is a glass that is supported by a carrier33, e.g., a semiconductor carrier 33, e.g., be based on silicon. Forexample, the arrangement 32, 33 may have been produced by coupling theenergy filter body 32 to the carrier by means of carrying out at leastone of a bonding step, e.g., an anodic bonding step, and a adhesionprocessing step. Steps 561, 562, 57 and 58 as schematically illustratedin FIG. 6 may be carried out in the same manner as has been explainedwith respect to FIG. 5 above, wherein in step 57, only a part of thecarrier 33 is removed so as to decrease the total thickness of thecarrier-glass-compound wafer arrangement 32, 33. Thecarrier-glass-compound wafer arrangement having the second structure 322may then serve as the energy filter 3.

Also in accordance with the embodiment schematically illustrated in FIG.7, the energy filter body material 32 is provided, in step 54, as a partof a carrier-glass-compound wafer arrangement 32, 33. For example, theenergy filter body material 32 is a glass that is supported by thecarrier 33, which may be based on silicon. However, in this embodiment,the energy filter body 32 may already be pre-structured on a side thatis not subjected to the step of structuring, in step 56, the energyfilter body 32 by using the preform 31. Steps 561 and 562 asschematically illustrated in FIG. 7 may be carried out in the samemanner as has been explained with respect to FIG. 5 above. Then, thecarrier 33 may be entirely removed, wherein said removing may comprise,in step 571, carrying out a grinding step so as to remove those sectionof the carrier 33 that do not contribute to the structure, and then, instep 572, carrying out an etch processing step so as to remove theremaining portion of the carrier 33. Thereby, a third structure 323 maybe established at the energy filter body 32. The third structure 323 maybe constituted by one or more legs 324 that laterally confine one ormore wells, as illustrated in FIG. 7. This third structure 323 mayfacilitate mechanical mounting of the energy filter 3, e.g., within thepower semiconductor device processing apparatus. Accordingly, the thirdstructure 323 may constitute a frame structure configured to be used formechanically mounting the energy filter 3. Thus, said frame structuremay be a stabilizing frame structure, in accordance with one or moreembodiments.

In accordance with the embodiment schematically illustrated in FIG. 8,similar to the embodiment schematically illustrated in FIG. 7, thesecond structure 322 may be established on a first side of the energyfilter body 32 and the third structure 323 may be established on asecond side of the energy filter body 32. But, in contrast to theembodiment of FIG. 7 according to which the third structure 323 may bedefined by the carrier 33, a second preform 35 may be created thatexhibits a further structure 355 and, during step 561, both the preform31 and the further preform 35 may be aligned with the energy filter body32. Then, in step 562, forces may be applied, e.g., simultaneously, toboth preforms 31 and 35 such that the preform 31 penetrates thesemiconductor body 32—which may have been softened before, e.g., bymeans of a temperature processing step—at its first side and such thatthe further preform 35 penetrates a semiconductor body 32 at its secondside. Thereby, both the second structure 322 and the third structure 323may be established, wherein the second structure 322 may becomplimentary to the first structure 311 and wherein the third structure323 may be complimentary to the further structure 355.

In an embodiment, the second structure 322 may be a micro structure or anano structure, whereas, as schematically illustrated in FIGS. 7 to 9,the third structure 323 may be substantially less fine as compared tothe second structure 322. For example, in an embodiment, the secondstructure 322 serves the purpose of energy diffusion, as has beenexplained with respect to FIG. 2, whereas the third structure 323 ratherserves the purpose of ensuring a stable mechanical installation of theenergy filter 3.

In accordance with the embodiment schematically illustrated in FIG. 9,steps 54 to 562 may be carried out in the same manner as has beenexplained with respect to FIG. 6. After carrying out step 562, a sectionof the carrier 33 may be removed, e.g., in a manner as has beenexplained with respect to step 57 illustrated in FIG. 6, e.g., bycarrying out grinding step and/or an etch processing step. Then, in step563, a mask 37, e.g., a hard mask 37, may be produced on the remaininglayer of the carrier 33, e.g., by means of carrying out a depositionand/or a structuring processing step. The mask 37 may comprise one ormore support means 371. For example, the support means 371 are alignedwith the interruptions 328 of the second structure 322 of the energyfilter body 32, e.g., the support means 371 are arranged at positionswhere the energy filter body 32 is later to be divided into at least twobodies within step 58. In step 564, the portions of the remaining layerof the carrier 33 that are not covered by the support means 371 may beremoved, e.g., by carrying out an etch processing step, thereby exposingthe second side of the energy filter body 32. Accordingly, the legs 324may be formed by a stack comprising a respective remaining part 333 ofthe carrier 33 and a respective support means 371. As has been explainedabove, the third structure 323 may be configured to facilitatemechanical mounting of the energy filter 3, e.g., within the powersemiconductor device processing apparatus. Accordingly, the thirdstructure 323 may constitute a frame structure, e.g., a stabilizingframe structure, as has been mentioned above.

In the above, embodiments pertaining to power semiconductor deviceprocessing methods were explained. For example, these semiconductordevices are based on silicon (Si). Accordingly, a monocrystallinesemiconductor region or layer, e.g., the region 10, 11, 12 and 15 ofexemplary embodiments, can be a monocrystalline Si-region or Si-layer.In other embodiments, polycrystalline or amorphous silicon may beemployed.

It should, however, be understood that the semiconductor body 10 andcomponents, e.g., regions 10, 11, 12 and 15 can be made of anysemiconductor material suitable for manufacturing a semiconductordevice. Examples of such materials include, without being limitedthereto, elementary semiconductor materials such as silicon (Si) orgermanium (Ge), group IV compound semiconductor materials such assilicon carbide (SiC) or silicon germanium (SiGe), binary, ternary orquaternary III-V semiconductor materials such as gallium nitride (GaN),gallium arsenide (GaAs), gallium phosphide (GaP), indium phosphide(InP), indium gallium phosphide (InGaPa), aluminum gallium nitride(AlGaN), aluminum indium nitride (AlInN), indium gallium nitride(InGaN), aluminum gallium indium nitride (AlGaInN) or indium galliumarsenide phosphide (InGaAsP), and binary or ternary II-VI semiconductormaterials such as cadmium telluride (CdTe) and mercury cadmium telluride(HgCdTe) to name few. The aforementioned semiconductor materials arealso referred to as “homojunction semiconductor materials”. Whencombining two different semiconductor materials a heterojunctionsemiconductor material is formed. Examples of heterojunctionsemiconductor materials include, without being limited thereto, aluminumgallium nitride (AlGaN)-aluminum gallium indium nitride (AlGaInN),indium gallium nitride (InGaN)-aluminum gallium indium nitride(AlGaInN), indium gallium nitride (InGaN)-gallium nitride (GaN),aluminum gallium nitride (AlGaN)-gallium nitride (GaN), indium galliumnitride (InGaN)-aluminum gallium nitride (AlGaN), silicon-siliconcarbide (SixCl-x) and silicon-SiGe heterojunction semiconductormaterials. For power semiconductor devices applications currently mainlySi, SiC, GaAs and GaN materials are used.

Spatially relative terms such as “under”, “below”, “lower”, “over”,“upper” and the like, are used for ease of description to explain thepositioning of one element relative to a second element. These terms areintended to encompass different orientations of the respective device inaddition to different orientations than those depicted in the figures.Further, terms such as “first”, “second”, and the like, are also used todescribe various elements, regions, sections, etc. and are also notintended to be limiting. Like terms refer to like elements throughoutthe description.

As used herein, the terms “having”, “containing”, “including”,“comprising”, “exhibiting” and the like are open ended terms thatindicate the presence of stated elements or features, but do notpreclude additional elements or features. The articles “a”, “an” and“the” are intended to include the plural as well as the singular, unlessthe context clearly indicates otherwise.

With the above range of variations and applications in mind, it shouldbe understood that the present invention is not limited by the foregoingdescription, nor is it limited by the accompanying drawings. Instead,the present invention is limited only by the following claims and theirlegal equivalents.

The invention claimed is:
 1. A method of producing an implantation ionenergy filter, comprising: creating a preform having a first structure;providing an energy filter body material, wherein the energy filter bodymaterial is an amorphous solid material; and structuring the energyfilter body material by using the preform, wherein the energy filterbody material comprises a glass, and wherein structuring the energyfilter body material includes warming up the glass to a temperature ofat least 90% of a glass-transition temperature of the energy filter bodymaterial, thereby establishing an energy filter body that is theamorphous solid material having a second structure.
 2. The method ofclaim 1, wherein the second structure is complementary to the firststructure.
 3. The method of claim 1, wherein structuring the energyfilter body material includes carrying out an imprint step using thepreform as a stamp.
 4. The method of claim 3, wherein the imprint stepincludes an embossing step.
 5. The method of claim 1, whereinstructuring the energy filter body material includes carrying out atleast one of casting processing step and a molding processing step. 6.The method of claim 1, wherein a plurality of energy filter bodies, eachof which having the second structure, are established by using the samepreform.
 7. The method of claim 1, wherein creating the preformcomprises processing a base layer by carrying out at least one of anetch processing step and a mechanical processing step, wherein theprocessed base layer forms the preform.
 8. The method of claim 1,wherein the preform is made of a material comprising at least one of asemiconductor, a ceramic, and a high-grade steel.
 9. The method of claim1, claims, wherein the energy filter body material is provided as a partof a carrier-glass-compound wafer arrangement.
 10. The method of claim1, wherein the second structure is established on a first side of theenergy filter body, and wherein the method further includes structuringa second side of the energy filter body so as to establish a thirdstructure at the second side of the energy filter body.
 11. The methodof claim 10, wherein structuring the second side of the energy filterbody includes: creating a further preform having a further structure;using the further preform for establishing the third structure at thesecond side of the glass energy filter body.
 12. The method of claim 11,wherein the third structure is complementary to the further structure.13. The method of claim 1, wherein the structured energy filter bodyforms the implantation ion energy filter.
 14. The method of claim 13,wherein the implantation ion energy filter is configured to receiveimplantation ions and to output received implantation ions such that theoutput implantation ions exhibit a reduced energy as compared to theirenergy when entering the implantation ion energy filter, wherein therespective amount of energy reduction depends on the point and/or angleof entry into the implantation ion energy filter.
 15. The method ofclaim 1, wherein provided energy filter body material is a glass. 16.The method of claim 15, wherein the glass comprises at least one ofborosilicate glass, a soda-lime glass, a float glass, a quartz glass, aporcelain, a polymer thermoplastic, a polymer glass, an acrylic glass,polycarbonate, polyethylene terephthalate, an undoped silica, a silicadoped with at least one dopant, the at least one dopant being selectedfrom a group containing boron, sodium, calcium, potassium and aluminum,zinc, copper, magnesium, germanium, a polymer, polynorbornene,polystyrene, polycarbonate, polyimide, and benzocyclobutene.